1. Field of the Invention
This invention is directed to electrical connectors comprising a plug and receptacle assembly for use in transmitting electrical signals on more than one signal path. This invention is more specifically directed to electrical connectors that do not require polarization. This electrical connector assembly employs axially spaced contacts in one connector and arcuately spaced contacts in a mating connector with the arcuately spaced contacts having axially spaced contact points to engage the axially spaced contacts in the mating electrical connector. This invention is also related to electrical connectors for use in automotive applications, such as electrical connectors for airbag inflation initiators or squibs.
2. Description of the Prior Art
Vehicle airbag systems typically include an airbag unit mounted within the cabin of the vehicle in order to protect the occupant in the event of an accident and a deceleration or other sensor that is typically not in the vicinity of the inflatable airbag. In order to deploy the airbag, an airbag inflation initiator or squib is activated in response to a signal from the sensor. The conventional squib unit typically contains an explosive material, such as gun powder, that is fired upon receipt of an electrical signal to cause the rapid release of high pressure gas to inflate the airbag. The squib is therefore typically part of the airbag unit. A squib electrical connector is normally mated to the airbag inflation initiator or squib in order to connect lead wires or other conductors leading from the sensor unit. The electrical connector system permits independent assembly of the airbag unit and the sensor or the remainder of the airbag system, and also permits subsequent connection and disconnection for servicing or repair.
Conventional squib units typically employ two terminal pins and when a current flows through both pins, the squib is activated and the airbag is inflated. Typically the two pins are located side by side. To prevent inadvertent actuation of the squib a shorting bar is normally mounted on both pins and when the squib connector is mated to the pins, the shorting bar is forced away from one of the pins. These conventional squib connector assemblies are also generally polarized so that the wrong pin is not connected to the sensor to permit inadvertent inflation of the airbag or to insure that the airbag will properly inflate upon receipt of a signal. In some cases, ferrites are also added to the interconnection system to prevent unwanted frequencies due to external interference.
U.S. Pat. No. 6,029,995 shows a relatively recent example of a mechanism for inflating an airbag as part of a vehicle restraint system. U.S. Pat. No. 5,435,754 and U.S. Pat. No. 5,653,606 show two examples of electrical connectors that can be employed with conventional squib units. U.S. Pat. 5,993,230 discloses a different technique in which a single pin connection is employed in conjunction with a surrounding electrically conductive annular ground plate so that the plug connector can be attached in what is termed and orientationless fashion.
The evolution of passive or supplemental vehicle restraint systems, such as airbags, has led to use of airbags in areas other than the vehicle dash. Side cushion airbags and smaller airbags protecting against other eventualities have been proposed and introduced. In some cases these other airbags must be assembled as a smaller unit, which has resulted in a demand for smaller electrical connector assemblies for use with these newer devices. In some cases, these airbags must be mounted in areas, such as door panels where space is limited. Therefore there is a need to eliminate the polarity or specific orientation of the electrical connector so that the airbag assembly will either fit in certain areas or can be assembled without excessive effort. Elimination of shorting clips and ferrites is also desirable if for no other reason than to eliminate the cost associated with those additional devices. One approach that has been considered for use with new smart airbag systems is to incorporate an active integrated circuit into the airbag unit or into the airbag inflation initiator or smart squib. This integrated circuit can then communicate with an external sensor or controller using two or three signal paths and the squib would be activated only upon receipt of a distinct signal pattern.
The nonpolarized electrical connector assembly of the present invention provides a means for connecting an airbag inflation initiator or squib, including a smart squib, with an external sensor or controller over two or three or more signal lines. This connector assembly eliminates the need for polarization and shorting clips as well as the need for ferrites. The connector assembly can also fit within a smaller envelope than conventional squib connectors. The plug connector can be positioned at any angle relative to the mating axis between the plug connector and the receptacle connector. The receptacle connector can be mated with the airbag initiator eliminating the need to mount the connector terminals in the squib itself. The plug connector can also be latched to the receptacle connector in any 360xc2x0 orientation. The connector assembly and the receptacle contacts are also suitable for transmitting signals of 50 ma. The invention depicted herein in the form of a preferred embodiment is an electrical connector assembly and a receptacle connector subassembly that accomplishes each of these objectives, and is adaptable to other applications and capabilities.
A receptacle connector subassembly, according to one aspect of this invention, is used to connect a mating plug having axially spaced plug contacts to an electronic component subassembly such as an airbag inflation initiator or squib. The receptacle connector subassembly includes a receptacle housing and a plurality of electrical contacts or terminals. The housing is partially insertable into a cavity in the electronic component subassembly. This housing receptacle has a plug passage defined by an curved surface, which receives a mating plug. A plurality of slots extend axially along the curved surface at arcuately spaced locations around the plug passage, and the receptacle contacts are inserted into these slots. Each receptacle contact has a electronic component mating section adjacent one end of the plug passage and a plug mating section closer to an opposite end of the respective receptacle contact. The plug mating sections of separate receptacle contacts are located at different axial positions in the plug passage so that individual receptacle contacts can each engage aligned ones of the axially spaced plug contacts when the mating plug is inserted into the plug passage of the receptacle housing. The mating plug need not be arcuately aligned relative to the individual receptacle contacts. In the preferred embodiment, a latch on the plug engages a latching shoulder on the receptacle housing for any mutual angular orientation between the plug and the receptacle. The receptacle is keyed relative to the electronic component or squib so that the receptacle terminals can be attached to leads or pins in the electronic component.
The receptacle contacts employed in the preferred embodiment of this invention each have a resilient beam extending in one direction from a central mounting section. A contact point on the resilient beam is spaced from the mounting section. The mounting section secures the receptacle contact in a connector housing. The receptacle contact also has a resilient component contact section extending in an opposite direction from the central mounting section. The component contact section including a contact slot open to one axial end of the receptacle contact. In the preferred embodiment of this invention the component contact section is in the form of a C-channel or clip. Both the contact slot and the contact point on the resilient beam are offset in the same direction relative to the mounting section so that both the contact point and the contact slot will protrude in the same direction relative to the housing when the receptacle contact in mounted in the housing.